As is well known, high speed computer and digital processing systems generally utilize arrangements of interconnected electronic devices. Advances in the field of electronics, however, have reached a stage where the inherent characteristics of electronic devices and interconnections of such devices are limiting factors. Optics is an attractive alternative to such electronic systems for very high speed processing. Systems utilizing optical arrangements to perform data functions are known in the art. U.S. Pat. No. 3,872,293, issued Mar. 18, 1975 to Eugene L. Green, discloses a multi-dimensional Fourier transform optical processor. U.S. Pat. No. 3,944,820 issued to Larry B. Stotts Mar. 16, 1976, discloses a high speed optical matrix multiplier system using analog processing techniques. U.S. Pat. No. 4,187,000, issued Feb. 5, 1980 to James N. Constant, describes an analog addressable optical computer and filter arrangement. These patents rely on analog computation techniques and are not applicable to digital processing of information.
U.S. Pat. No. 4,418,394, issued to Anthony M. Tai on Nov. 29, 1983, discloses an optical residue arithmetic computer having a programmable computation module in which optical paths are determined by electrical fields. While optical techniques are capable of very high speed operation, the required switching of electrical fields is relatively slow, and the use of such electrical field detracts from the processing speed obtainable when radiant energy is used alone.
U.S. Pat. No. 3,996,455, issued to Schaefer et al Dec. 7, 1976, discloses two-dimensional radiant energy array computers and computing devices operating in parallel on rectangular arrays of digital radiant energy optical signal elements. The logic operations on the arrays, however, are performed by various electrical, optical, electro-optical and opto-electrical devices. Consequently, the control of the Schaefer et al radiant energy computer is relatively complex.
The article "Optical Logic Array Processor Using Shadowgrams" by J. Tanida and Y. Ichioka appearing in the Journal of the Optical Society of America, Vol. 73, No. 6, June 1983, pp. 800-809, discloses a method of implementing digital logic gates on the basis of a lensless shadow-casting technique in which shadows cast by selectively positioned light sources are passed through prescribed masking arrangements to perform logical functions. The shadowgram arrangement utilizes precise positioning of incoherent light sources to define the logic function to be performed and specialized masking arrangements to code input information and to detect the logical output. As a result, the shadowgram technique can perform specialized optical processing but is not adapted to general purpose data processing and computing functions requiring iterations of different types of optical operations.
The articles "Parallel Algorithms for Optical Digital Computers" by A. Huang, 10th International Optical Computing Conference, IEEE (Cat. No. 83CH1880-4), pp. 13-17, Apr. 6, 1983, and "An Optical Processor Based on Symbolic Substitution" by K. H. Brenner and A. Huang appearing in the Optical Computing Technical Digest, Winter 1985, disclose digital processors in which two-dimensional input images are spatially combined with the two-dimensional output images of the processors. Rather than using Boolean type logic gating, the spatial combination is based on symbolic substitution in which patterns in an array of radiant energy beams are detected to form prescribed patterns in an output array of light beams. The radiant energy serial symbolic substitution requires manipulation of a two-dimensional cellular logic array for which an arrangement of beam serial shifting devices and controlled shutters is described. It is an object of the invention to provide improved arrangements to process radiant energy spatial digital information that may incorporate parallel processing techniques.